Brian Smith wrote: > >Sure SysV semaphores are thread-safe. When a thread blocks on > >one, the entire process blocks (no threads run). You won't > >get any safer than that ;-) > > Yikes that isn't good. Is that only in STABLE? or does CURRENT > do that as well? I guess I'll have to protect the semop() call > with a pthread mutex to prevent two threads locking a single > semaphore by the same process (creating a deadlock situation). > > Is this the recommended method of preventing these problems?
Yeah: don't make blocking system calls for which there are no asynchronous equivalents. Use the POSIX interfaces for use by pthreads, instead. > (the SysV semaphore is protecting shared memory accessed by > multiple processes). > > Thanks for the info... it explains alot! Use mmap of a backing-store file, and then use file locking to do record locking in the shared memory segment. -- Terry To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-current" in the body of the message
